A light emitting element in an ultraviolet region is greatly expected especially in realization of a mercury free fluorescent lamp, a photo catalyst providing a clean environment, a DVD of the new generation realizing higher density recording, and the like. From such a background, a GaN blue light emitting element is realized (for example, refer to a patent document 1).
The patent document 1 describes a light emitting element including a sapphire substrate, a buffer layer formed on the sapphire substrate, an n-type cladding layer formed of an n-type gallium nitride compound semiconductor layer and formed on the buffer layer, a non-doped active layer, a p-type cladding layer formed of a p-type gallium nitride compound semiconductor layer, and a p-type contact layer having a high carrier concentration. This conventional GaN blue light emitting element emits a light having an emission wavelength of 370 nm.
Patent document 1: Japanese Patent No. 2778405 (FIG. 1)